Quasillites (Quasillites) quasilitiformis ( Polenova, 1952 )

Maillet, Sebastien, Milhau, Bruno, Vreulx, Michel & Posada, Luis-Carlos Sánchez De, 2016, Givetian ostracods of the Candás Formation (Asturias, North-western Spain): taxonomy, stratigraphy, palaeoecology, relationship to global events and palaeogeographical implications, Zootaxa 4068 (1), pp. 1-78 : 44

Quasillites (Quasillites) quasilitiformis ( Polenova, 1952)

(Pl. III: Fig. 4 )

1952 Costatia quasilitiformis nov. sp.; Polenova: 112–113, pl. 9, fig. 1.

1983 Quasillites quasillitiformis (Polenova) ; Żbikowska: 52, pl. 14, figs. 1–9.

1988 Quasillites (Quasillites) quasillitiformis (Polenova) ; Becker: 413.

? 1993 Costatia cf. quasillitiformis Polenova ; Lethiers & Racheboeuf: 598, pl. 3, figs. 11–12. 1993 Quasillites (Quasillites) quasillitiformis (Polenova) ; Kasimi: pl. 17, fig. 19. 2013 Quasillites (Quasillites) quasillitiformis (Polenova) ; Maillet: 124, pl. XVI, fig. 15.

Material. 16 specimens (11 C, 3 V, 2 F).

Diagnosis. Polenova (1952, p. 112).

Description. Medium-sized carapace, sub-rectangular in lateral and dorsal views. Very slight overlap of the larger LV over the RV at free margins of the carapace. Hmax at 1/4 anterior; Lmax median; Wmax median. Almost straight dorsal margin, slightly concave at mid-length. Straight ventral margin. Ventral and dorsal margins parallel. Slight dorsal depression of the carapace at mid-length. Anterior margin convex at its extremities, straight in its middle. Convex posterior margin. Anterior part of the carapace higher than the posterior one. Surface ornamented by fine parallel ridges, longitudinal in the 3/4 posterior of the carapace and becoming incurved anteriorly, pointing towards the antero-ventral part. Small postero-ventral spine or node.

Discussion. Although not very well preserved, these specimens show all the features of Quasillites (Quasillites) quasilitiformis ( Polenova, 1952) . Several of our specimens, including the one figured (Pl. III: Fig. 4 ), show however a quite high carapace for the species.

Occurrences. Upper Givetian (Huergas Fm and Candás Fm, mbs C and D), Asturias (Peran-Perlora and Huergas Fms); Givetian, Ardenne, Russia and Poland.

Figures

FIGURE 4. Height / length diagram for Evlanella peranensis Maillet n. sp .. The trendline equation (y) is indicated.